NTT Docomo’s Advanced C-RAN Architecture


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NTT Docomo’s Advanced C-RAN Architecture

  1. 1. Feb. 2014 ~2014.02 Current C-RAN 2015 Advanced C-RAN Going Advanced = C-RAN Kept RRHs away/separate from BBUs, by moving all BBUs to NTT’s CO and leaving RRHs at their current location in Macro cell sites R R Macro RRH (Remote Radio Head) Macro cell + 1. C-RAN 2. Small Cell/Hetnet C-RAN: Centralized/Cloud RAN BBU: Baseband Unit RRH: Remote Radio Head Macro RRH R 3. Carrier Aggregation CA between Macro and Small cells CA between Small cells CA between Macro cells Small RRH Low power small optical remote radio equipment Band A NTT Docomo’s LTE bands Macro cell 3. Carrier Aggregation Band B RR R R CPRI pico Band C CPRI R R NTT CO eNB + More distance between Making Small RRHs lighter BBUs and RRHs and cheaper 1) 700MHz band (LTE: 10MHz) 2) 800MHz band (LTE) 3) 1.5GHz band (LTE: 15MHz) 4) 1.7GHz band (LTE: 20MHz) 5) 2GHz band (LTE: 10MHz) NTT CO 2. Add on Small cell BBU BBU BBU Band A RRH RU RU R Band B RRH RU RU Band C CPRI RRH CPRI Carrier Aggregation WD M BBU High-density BS: a single BBU covers up to 48 RRHs eNB CA between macro and small cell - no interference from macro cell to small cell and enhanced data speed and capacity by small cell All processing (CA and Hand-Over) within eNodeB (BBU) Current Fronthaul Enhanced Fronthaul • P2P CPRI transmission • CPRI Rate: ~ 2.5Gbps (2x2, 20MHz: IP rate = 150Mbps) • Dedicated fiber (dark fiber) • Fronthaul Options currently under reviewed by NTT: Fiber per RRH, Active WDM, WDM-PON, TDM-PON, … • Key Parameters: i) Capacity & Latency for CPRI Transmission, ii) Cost No Carrier Aggregation has been employed yet (commercialization scheduled in 2015) n Launched 150 Mbps service using 20 MHz (wideband) at 1.7 GHz in Oct. 2013 n n Deploying more small cells to cover local areas with high traffic (e.g. highly crowded areas) in macro cells covering wide areas à building HetNet environment and employing inter-cell carrier aggregation à enhanced capacity n In Feb. 2013, Advanced-RAN Plan announced (equipment development and commercialization to be completed by 2015) In Feb ~ March, 2013, vendors selected: Panasonic, Fujitsu, NEC, NSN, etc. to develop 1) BBUs (48 RRHs/BBU) and 2) small RRHs Netmanias ONE-SHOT
  2. 2. Feb. 2014 Source: NTT Docomo, “Development of LTA-Advanced”, CTIA 2013 References [2013/11] NTT Docomo, “Examining the fronthaul opportunities for future radio access”, Cellular Backhaul Summit [2013/09] NTT Docomo, “The Dawn of 5G”, IEEE 78th Vehicular Technology Conference [2013/05] NTT Docomo, “Development of LTA-Advanced”, CTIA 2013 Netmanias ONE-SHOT